Subject: [PATCH v8 2/3] CMDQ: Mediatek CMDQ driver

From: [email-masked] (Matthias Brugger)
Date: Thu, 2 Jun 2016 10:46:28 +0200

On 01/06/16 11:57, Horng-Shyang Liao wrote:
> Hi Mathias,
>
> Please see my inline reply.
>
> On Tue, 2016-05-31 at 22:04 +0200, Matthias Brugger wrote:
>>
>> On 31/05/16 10:36, Horng-Shyang Liao wrote:
>>> Hi Mathias,
>>>
>>> Please see my inline reply.
>>>
>>> On Mon, 2016-05-30 at 17:31 +0200, Matthias Brugger wrote:
>>>>
>>>> On 30/05/16 05:19, HS Liao wrote:
>>>>> This patch is first version of Mediatek Command Queue(CMDQ) driver. The
>>>>> CMDQ is used to help read/write registers with critical time limitation,
>>>>> such as updating display configuration during the vblank. It controls
>>>>> Global Command Engine (GCE) hardware to achieve this requirement.
>>>>> Currently, CMDQ only supports display related hardwares, but we expect
>>>>> it can be extended to other hardwares for future requirements.
>>>>>
>>>>> Signed-off-by: HS Liao <[email-masked]>
>>>>> Signed-off-by: CK Hu <[email-masked]>
>>>>> ---
>>>>>     drivers/soc/mediatek/Kconfig    |  10 +
>>>>>     drivers/soc/mediatek/Makefile   |   1 +
>>>>>     drivers/soc/mediatek/mtk-cmdq.c | 943 ++++++++++++++++++++++++++++++++++++++++
>>>>>     include/soc/mediatek/cmdq.h     | 197 +++++++++
>>>>>     4 files changed, 1151 insertions(+)
>>>>>     create mode 100644 drivers/soc/mediatek/mtk-cmdq.c
>>>>>     create mode 100644 include/soc/mediatek/cmdq.h
>>>>>
>>>>> diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
>>>>> index 0a4ea80..c4ad75c 100644
>>>>> --- a/drivers/soc/mediatek/Kconfig
>>>>> +++ b/drivers/soc/mediatek/Kconfig
>>>>> @@ -1,6 +1,16 @@
>>>>>     #
>>>>>     # MediaTek SoC drivers
>>>>>     #
>>>>> +config MTK_CMDQ
>>>>> +	bool "MediaTek CMDQ Support"
>>>>> +	depends on ARCH_MEDIATEK || COMPILE_TEST
>>
>> depends on ARM64 ?
>
> Will add ARM64.
>
>>>>> +	select MTK_INFRACFG
>>>>> +	help
>>>>> +	  Say yes here to add support for the MediaTek Command Queue (CMDQ)
>>>>> +	  driver. The CMDQ is used to help read/write registers with critical
>>>>> +	  time limitation, such as updating display configuration during the
>>>>> +	  vblank.
>>>>> +
>>>>>     config MTK_INFRACFG
>>>>>     	bool "MediaTek INFRACFG Support"
>>>>>     	depends on ARCH_MEDIATEK || COMPILE_TEST
>>>>> diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
>>>>> index 12998b0..f7397ef 100644
>>>>> --- a/drivers/soc/mediatek/Makefile
>>>>> +++ b/drivers/soc/mediatek/Makefile
>>>>> @@ -1,3 +1,4 @@
>>>>> +obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq.o
>>>>>     obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
>>>>>     obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
>>>>>     obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
>>>>> diff --git a/drivers/soc/mediatek/mtk-cmdq.c b/drivers/soc/mediatek/mtk-cmdq.c
>>>>> new file mode 100644
>>>>> index 0000000..e9d6e1c
>>>>> --- /dev/null
>>>>> +++ b/drivers/soc/mediatek/mtk-cmdq.c
>>>>> @@ -0,0 +1,943 @@
>>>>> +/*
>>>>> + * Copyright (c) 2015 MediaTek Inc.
>>>>> + *
>>>>> + * This program is free software; you can redistribute it and/or modify
>>>>> + * it under the terms of the GNU General Public License version 2 as
>>>>> + * published by the Free Software Foundation.
>>>>> + *
>>>>> + * This program is distributed in the hope that it will be useful,
>>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>>>> + * GNU General Public License for more details.
>>>>> + */
>>>>> +
>>>>> +#include <linux/clk.h>
>>>>> +#include <linux/clk-provider.h>
>>>>> +#include <linux/completion.h>
>>>>> +#include <linux/dma-mapping.h>
>>>>> +#include <linux/errno.h>
>>>>> +#include <linux/interrupt.h>
>>>>> +#include <linux/iopoll.h>
>>>>> +#include <linux/kernel.h>
>>>>> +#include <linux/kthread.h>
>>>>> +#include <linux/module.h>
>>>>> +#include <linux/mutex.h>
>>>>> +#include <linux/of_address.h>
>>>>> +#include <linux/of_irq.h>
>>>>> +#include <linux/platform_device.h>
>>>>> +#include <linux/slab.h>
>>>>> +#include <linux/spinlock.h>
>>>>> +#include <linux/suspend.h>
>>>>> +#include <linux/workqueue.h>
>>>>> +#include <soc/mediatek/cmdq.h>
>>>>> +
>>>>> +#define CMDQ_INITIAL_CMD_BLOCK_SIZE	PAGE_SIZE
>>>>> +#define CMDQ_INST_SIZE			8 /* instruction is 64-bit */
>>>>> +#define CMDQ_TIMEOUT_MS			1000
>>>>> +#define CMDQ_IRQ_MASK			0xffff
>>>>> +#define CMDQ_DRIVER_DEVICE_NAME		"mtk_cmdq"
>>>>> +#define CMDQ_CLK_NAME			"gce"
>>>>
>>>> We can put the names in directly to un-bloat the defines.
>>>
>>> I will use the names directly and remove defines.
>>>
>>>>> +
>>>>> +#define CMDQ_CURR_IRQ_STATUS		0x010
>>>>> +#define CMDQ_CURR_LOADED_THR		0x018
>>>>> +#define CMDQ_THR_SLOT_CYCLES		0x030
>>>>> +
>>>>> +#define CMDQ_THR_BASE			0x100
>>>>> +#define CMDQ_THR_SHIFT			0x080
>>>>
>>>> Wouldn't be CMDQ_THR_SIZE more accurate?
>>>
>>> Will rename it.
>>>
>>>>> +#define CMDQ_THR_WARM_RESET		0x00
>>>>> +#define CMDQ_THR_ENABLE_TASK		0x04
>>>>> +#define CMDQ_THR_SUSPEND_TASK		0x08
>>>>> +#define CMDQ_THR_CURR_STATUS		0x0c
>>>>> +#define CMDQ_THR_IRQ_STATUS		0x10
>>>>> +#define CMDQ_THR_IRQ_ENABLE		0x14
>>>>> +#define CMDQ_THR_CURR_ADDR		0x20
>>>>> +#define CMDQ_THR_END_ADDR		0x24
>>>>> +#define CMDQ_THR_CFG			0x40
>>>>> +
>>>>> +#define CMDQ_THR_ENABLED		0x1
>>>>> +#define CMDQ_THR_DISABLED		0x0
>>>>> +#define CMDQ_THR_SUSPEND		0x1
>>>>> +#define CMDQ_THR_RESUME			0x0
>>>>> +#define CMDQ_THR_STATUS_SUSPENDED	BIT(1)
>>>>> +#define CMDQ_THR_DO_WARM_RESET		BIT(0)
>>>>> +#define CMDQ_THR_ACTIVE_SLOT_CYCLES	0x3200
>>>>> +#define CMDQ_THR_PRIORITY		3
>>>>> +#define CMDQ_THR_IRQ_DONE		0x1
>>>>> +#define CMDQ_THR_IRQ_ERROR		0x12
>>>>> +#define CMDQ_THR_IRQ_EN			0x13 /* done + error */
>>>>
>>>> #define CMDQ_THR_IRQ_EN (CMDQ_THR_IRQ_ERROR | CMDQ_THR_IRQ_DONE)
>>>
>>> Will do.
>>>
>>>>> +#define CMDQ_THR_IRQ_MASK		0x13
>>>>
>>>> never used.
>>>
>>> Will remove.
>>>
>>>>> +#define CMDQ_THR_EXECUTING		BIT(31)
>>>>> +
>>>>> +#define CMDQ_ARG_A_WRITE_MASK		0xffff
>>>>> +#define CMDQ_SUBSYS_MASK		0x1f
>>>>> +#define CMDQ_OP_CODE_MASK		0xff000000
>>>>> +
>>>>> +#define CMDQ_OP_CODE_SHIFT		24
>>>>
>>>> Couldn't we connect the mask with the shift, or aren't they related?
>>>>
>>>> #define CMDQ_OP_CODE_MASK (0xff << CMDQ_OP_CODE_SHIFT)
>>>
>>> Will do.
>>>
>>>>> +#define CMDQ_SUBSYS_SHIFT		16
>>>>> +
>>>>> +#define CMDQ_WRITE_ENABLE_MASK		BIT(0)
>>>>> +#define CMDQ_JUMP_BY_OFFSET		0x10000000
>>>>> +#define CMDQ_JUMP_BY_PA			0x10000001
>>>>> +#define CMDQ_JUMP_PASS			CMDQ_INST_SIZE
>>>>> +#define CMDQ_WFE_UPDATE			BIT(31)
>>>>> +#define CMDQ_WFE_WAIT			BIT(15)
>>>>> +#define CMDQ_WFE_WAIT_VALUE		0x1
>>>>> +#define CMDQ_EOC_IRQ_EN			BIT(0)
>>>>> +
>>>>> +enum cmdq_thread_index {
>>>>> +	CMDQ_THR_DISP_MAIN_IDX,	/* main */
>>>>> +	CMDQ_THR_DISP_SUB_IDX,	/* sub */
>>>>> +	CMDQ_THR_DISP_MISC_IDX,	/* misc */
>>>>> +	CMDQ_THR_MAX_COUNT,	/* max */
>>>>> +};
>>>>> +
>>>>> +/*
>>>>> + * CMDQ_CODE_MOVE:
>>>>> + *   move value into internal register as mask
>>>>> + *   format: op mask
>>>>> + * CMDQ_CODE_WRITE:
>>>>> + *   write value into target register
>>>>> + *   format: op subsys address value
>>>>> + * CMDQ_CODE_JUMP:
>>>>> + *   jump by offset
>>>>> + *   format: op offset
>>>>> + * CMDQ_CODE_WFE:
>>>>> + *   wait for event and clear
>>>>> + *   it is just clear if no wait
>>>>> + *   format: [wait]  op event update:1 to_wait:1 wait:1
>>>>> + *           [clear] op event update:1 to_wait:0 wait:0
>>>>> + * CMDQ_CODE_EOC:
>>>>> + *   end of command
>>>>> + *   format: op irq_flag
>>>>> + */
>>>>
>>>> I think we need more documentation of how this command queue engine is
>>>> working. If not, I think it will be really complicated to understand how
>>>> to use this.
>>>>
>>>>> +enum cmdq_code {
>>>>> +	CMDQ_CODE_MOVE = 0x02,
>>>>> +	CMDQ_CODE_WRITE = 0x04,
>>>>> +	CMDQ_CODE_JUMP = 0x10,
>>>>> +	CMDQ_CODE_WFE = 0x20,
>>>>> +	CMDQ_CODE_EOC = 0x40,
>>>>> +};
>>>>> +
>>>>> +enum cmdq_task_state {
>>>>> +	TASK_STATE_BUSY, /* running on a GCE thread */
>>>>> +	TASK_STATE_ERROR,
>>>>> +	TASK_STATE_DONE,
>>>>> +};
>>>>> +
>>>>> +struct cmdq_task_cb {
>>>>> +	cmdq_async_flush_cb	cb;
>>>>> +	void			*data;
>>>>> +};
>>>>> +
>>>>> +struct cmdq_thread {
>>>>> +	void __iomem		*base;
>>>>> +	struct list_head	task_busy_list;
>>>>> +	wait_queue_head_t	wait_task_done;
>>>>> +};
>>>>> +
>>>>> +struct cmdq_task {
>>>>> +	struct cmdq		*cmdq;
>>>>> +	struct list_head	list_entry;
>>>>> +	enum cmdq_task_state	task_state;
>>>>> +	void			*va_base;
>>>>> +	dma_addr_t		pa_base;
>>>>> +	u64			engine_flag;
>>>>> +	size_t			command_size;
>>>>> +	u32			num_cmd;
>>>>
>>>> num_cmd is directly connected to command_size. I prefer to just keep
>>>> num_cmd and calculate the command_size where necessary.
>>>
>>> After I trace code, I prefer to keep command_size and calculate num_cmd
>>> where necessary. What do you think?
>>>
>>
>> I suppose you prefer this, as you are writing to the GCE depending on
>> the command_size. I think it is worth to create a macro for the
>> calculation of the number of commands, to make the code more readable.
>> Would be nice if you would just pass cmdq_task to it and it would return
>> the number. Just as an idea.
>
> Will add macro.
>
>>>>> +	struct cmdq_thread	*thread;
>>>>> +	struct cmdq_task_cb	cb;
>>>>> +	struct work_struct	release_work;
>>>>> +};
>>>>> +
>>>>> +struct cmdq {
>>>>> +	struct device		*dev;
>>>>> +	void __iomem		*base;
>>>>> +	u32			irq;
>>>>> +	struct workqueue_struct	*task_release_wq;
>>>>> +	struct cmdq_thread	thread[CMDQ_THR_MAX_COUNT];
>>>>> +	struct mutex		task_mutex;	/* for task */
>>>>> +	spinlock_t		exec_lock;	/* for exec */
>>>>> +	struct clk		*clock;
>>>>> +	bool			suspended;
>>>>> +};
>>>>> +
>>>>> +struct cmdq_subsys {
>>>>> +	u32	base;
>>>>> +	int	id;
>>>>> +};
>>>>> +
>>>>> +static const struct cmdq_subsys gce_subsys[] = {
>>>>> +	{0x1400, 1},
>>>>> +	{0x1401, 2},
>>>>> +	{0x1402, 3},
>>>>> +};
>>>>> +
>>>>> +static int cmdq_subsys_base_to_id(u32 base)
>>>>> +{
>>>>> +	int i;
>>>>> +
>>>>> +	for (i = 0; i < ARRAY_SIZE(gce_subsys); i++)
>>>>> +		if (gce_subsys[i].base == base)
>>>>> +			return gce_subsys[i].id;
>>>>> +	return -EFAULT;
>>>>> +}
>>>>> +
>>>>> +static int cmdq_eng_get_thread(u64 flag)
>>>>> +{
>>>>> +	if (flag & BIT_ULL(CMDQ_ENG_DISP_DSI0))
>>>>> +		return CMDQ_THR_DISP_MAIN_IDX;
>>>>> +	else if (flag & BIT_ULL(CMDQ_ENG_DISP_DPI0))
>>>>> +		return CMDQ_THR_DISP_SUB_IDX;
>>>>> +	else
>>>>> +		return CMDQ_THR_DISP_MISC_IDX;
>>>>> +}
>>>>> +
>>>>> +static void cmdq_task_release(struct cmdq_task *task)
>>>>> +{
>>>>> +	struct cmdq *cmdq = task->cmdq;
>>>>> +
>>>>> +	dma_free_coherent(cmdq->dev, task->command_size, task->va_base,
>>>>> +			  task->pa_base);
>>>>> +	kfree(task);
>>>>> +}
>>>>> +
>>>>> +static struct cmdq_task *cmdq_task_acquire(struct cmdq_rec *rec,
>>>>> +					   struct cmdq_task_cb cb)
>>>>> +{
>>>>> +	struct cmdq *cmdq = rec->cmdq;
>>>>> +	struct device *dev = cmdq->dev;
>>>>> +	struct cmdq_task *task;
>>>>> +
>>>>> +	task = kzalloc(sizeof(*task), GFP_KERNEL);
>>>>> +	INIT_LIST_HEAD(&task->list_entry);
>>>>> +	task->va_base = dma_alloc_coherent(dev, rec->command_size,
>>>>> +					   &task->pa_base, GFP_KERNEL);
>>>>> +	if (!task->va_base) {
>>>>> +		dev_err(dev, "allocate command buffer failed\n");
>>>>> +		kfree(task);
>>>>> +		return NULL;
>>>>> +	}
>>>>> +
>>>>> +	task->cmdq = cmdq;
>>>>> +	task->command_size = rec->command_size;
>>>>> +	task->engine_flag = rec->engine_flag;
>>>>> +	task->task_state = TASK_STATE_BUSY;
>>>>> +	task->cb = cb;
>>>>> +	memcpy(task->va_base, rec->buf, rec->command_size);
>>>>> +	task->num_cmd = task->command_size / CMDQ_INST_SIZE;
>>>>> +	return task;
>>>>> +}
>>>>> +
>>>>> +static void cmdq_thread_writel(struct cmdq_thread *thread, u32 value,
>>>>> +			       u32 offset)
>>>>> +{
>>>>> +	writel(value, thread->base + offset);
>>>>> +}
>>>>> +
>>>>> +static u32 cmdq_thread_readl(struct cmdq_thread *thread, u32 offset)
>>>>> +{
>>>>> +	return readl(thread->base + offset);
>>>>> +}
>>>>
>>>> We can get rid of cmdq_thread_readl/writel.
>>>
>>> Will do.
>>>
>>>>> +
>>>>> +static int cmdq_thread_suspend(struct cmdq *cmdq, struct cmdq_thread *thread)
>>>>> +{
>>>>> +	u32 status;
>>>>> +
>>>>> +	cmdq_thread_writel(thread, CMDQ_THR_SUSPEND, CMDQ_THR_SUSPEND_TASK);
>>>>> +
>>>>> +	/* If already disabled, treat as suspended successful. */
>>>>> +	if (!(cmdq_thread_readl(thread, CMDQ_THR_ENABLE_TASK) &
>>>>> +	      CMDQ_THR_ENABLED))
>>>>> +		return 0;
>>>>> +
>>>>> +	if (readl_poll_timeout_atomic(thread->base + CMDQ_THR_CURR_STATUS,
>>>>> +			status, status & CMDQ_THR_STATUS_SUSPENDED, 0, 10)) {
>>>>> +		dev_err(cmdq->dev, "suspend GCE thread 0x%x failed\n",
>>>>> +			(u32)(thread->base - cmdq->base));
>>>>> +		return -EFAULT;
>>>>> +	}
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static void cmdq_thread_resume(struct cmdq_thread *thread)
>>>>> +{
>>>>> +	cmdq_thread_writel(thread, CMDQ_THR_RESUME, CMDQ_THR_SUSPEND_TASK);
>>>>> +}
>>>>> +
>>>>> +static int cmdq_thread_reset(struct cmdq *cmdq, struct cmdq_thread *thread)
>>>>> +{
>>>>> +	u32 warm_reset;
>>>>> +
>>>>> +	cmdq_thread_writel(thread, CMDQ_THR_DO_WARM_RESET, CMDQ_THR_WARM_RESET);
>>>>> +	if (readl_poll_timeout_atomic(thread->base + CMDQ_THR_WARM_RESET,
>>>>> +			warm_reset, !(warm_reset & CMDQ_THR_DO_WARM_RESET),
>>>>> +			0, 10)) {
>>>>> +		dev_err(cmdq->dev, "reset GCE thread 0x%x failed\n",
>>>>> +			(u32)(thread->base - cmdq->base));
>>>>> +		return -EFAULT;
>>>>> +	}
>>>>> +	writel(CMDQ_THR_ACTIVE_SLOT_CYCLES, cmdq->base + CMDQ_THR_SLOT_CYCLES);
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static void cmdq_thread_disable(struct cmdq *cmdq, struct cmdq_thread *thread)
>>>>> +{
>>>>> +	cmdq_thread_reset(cmdq, thread);
>>>>> +	cmdq_thread_writel(thread, CMDQ_THR_DISABLED, CMDQ_THR_ENABLE_TASK);
>>>>> +}
>>>>> +
>>>>> +/* notify GCE to re-fetch commands by setting GCE thread PC */
>>>>> +static void cmdq_thread_invalidate_fetched_data(struct cmdq_thread *thread)
>>>>> +{
>>>>> +	cmdq_thread_writel(thread,
>>>>> +			   cmdq_thread_readl(thread, CMDQ_THR_CURR_ADDR),
>>>>> +			   CMDQ_THR_CURR_ADDR);
>>>>> +}
>>>>> +
>>>>> +static void cmdq_task_insert_into_thread(struct cmdq_task *task)
>>>>> +{
>>>>> +	struct cmdq_thread *thread = task->thread;
>>>>> +	struct cmdq_task *prev_task = list_last_entry(
>>>>> +			&thread->task_busy_list, typeof(*task), list_entry);
>>>>> +	u64 *prev_task_base = prev_task->va_base;
>>>>> +
>>>>> +	/* let previous task jump to this task */
>>>>> +	prev_task_base[prev_task->num_cmd - 1] = (u64)CMDQ_JUMP_BY_PA << 32 |
>>>>> +						 task->pa_base;
>>>>> +
>>>>> +	cmdq_thread_invalidate_fetched_data(thread);
>>>>> +}
>>>>> +
>>>>> +/* we assume tasks in the same display GCE thread are waiting the same event. */
>>>>> +static void cmdq_task_remove_wfe(struct cmdq_task *task)
>>>>> +{
>>>>> +	u32 wfe_option = CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | CMDQ_WFE_WAIT_VALUE;
>>>>> +	u32 wfe_op = CMDQ_CODE_WFE << CMDQ_OP_CODE_SHIFT;
>>>>> +	u32 *base = task->va_base;
>>>>> +	u32 num_cmd = task->num_cmd << 1;
>>>>> +	int i;
>>>>> +
>>>>> +	for (i = 0; i < num_cmd; i += 2)
>>>>> +		if (base[i] == wfe_option &&
>>>>> +		    (base[i + 1] & CMDQ_OP_CODE_MASK) == wfe_op) {
>>>>> +			base[i] = CMDQ_JUMP_PASS;
>>>>> +			base[i + 1] = CMDQ_JUMP_BY_OFFSET;
>>>>> +		}
>>>>
>>>> After using the command buffer as a void pointer a u64 pointer, we now
>>>> reference to it as u32. I would prefer to explain here, how the command
>>>> looks like we are searching for and use a for loop passing task->num_cmd
>>>> instead.
>>>
>>> Will use u64* to rewrite the above code.
>>>
>>>>> +}
>>>>> +
>>>>> +static void cmdq_task_exec(struct cmdq_task *task, struct cmdq_thread *thread)
>>>>> +{
>>>>> +	struct cmdq *cmdq = task->cmdq;
>>>>> +	unsigned long flags;
>>>>> +	unsigned long curr_pa, end_pa;
>>>>> +
>>>>> +	WARN_ON(clk_prepare_enable(cmdq->clock) < 0);
>>>>> +	spin_lock_irqsave(&cmdq->exec_lock, flags);
>>>>
>>>> cmdq_task_exec is called with cmdq->task_mutex held, so why do we need
>>>> the spin_lock here? Can't we just use one of the two?
>>>
>>> We can drop task_mutex, but we will get some side effects.
>>> 1. exec_lock needs to include more code, but I think it is not good for
>>>      spinlock.
>>> 2. In cmdq_rec_flush_async(), task_mutex needs to protect
>>>      (1) cmdq->suspended, (2) cmdq_task_exec(), and
>>>      (3) cmdq_task_wait_release_schedule().
>>>      If we drop task_mutex, we have to put cmdq->suspended if condition
>>>      just before cmdq_task_exec() and inside exec_lock, and we have to
>>>      release task and its command buffer if error. This will let flow
>>>      become more complex and enlarge code size.
>>>
>>> What do you think?
>>
>> Why do you need to protect cmdq_task_wait_release_schedule? We don't
>> care about the order of the workqueue elements, do we?
>
> According to CK's comment, we have to ensure order to remove previous
> task.
> http://lists.infradead.org/pipermail/linux-mediatek/2016-May/005547.html
>
>> As far as I understand you would need to protect cmdq_task_acquire as
>> well, to "ensure" continously growing pa_base. More on that below.
>
> We need to ensure continuous physical addresses in a task, but we don't
> need to ensure continuous physical addresses between tasks.
> So, I think it is unnecessary to protect by mutex or spinlock.
>

True, I didn't get that.

>>>
>>>>> +	task->thread = thread;
>>>>> +	task->task_state = TASK_STATE_BUSY;
>>>>
>>>> That was already set in cmdq_task_acquire, why do we need to set it here
>>>> again?
>>>
>>> Will drop it.
>>>
>>
>> Yeah, but I think it makes more sense to drop it in cmdq_task_acquire
>> instead.
>
> Will drop it in cmdq_task_acquire instead.
>
>>>>> +	if (list_empty(&thread->task_busy_list)) {
>>>>> +		WARN_ON(cmdq_thread_reset(cmdq, thread) < 0);
>>>>> +
>>>>> +		cmdq_thread_writel(thread, task->pa_base, CMDQ_THR_CURR_ADDR);
>>>>> +		cmdq_thread_writel(thread, task->pa_base + task->command_size,
>>>>> +				   CMDQ_THR_END_ADDR);
>>>>> +		cmdq_thread_writel(thread, CMDQ_THR_PRIORITY, CMDQ_THR_CFG);
>>>>> +		cmdq_thread_writel(thread, CMDQ_THR_IRQ_EN,
>>>>> +				   CMDQ_THR_IRQ_ENABLE);
>>>>> +
>>>>> +		cmdq_thread_writel(thread, CMDQ_THR_ENABLED,
>>>>> +				   CMDQ_THR_ENABLE_TASK);
>>>>> +	} else {
>>>>> +		WARN_ON(cmdq_thread_suspend(cmdq, thread) < 0);
>>>>> +
>>>>> +		/*
>>>>> +		 * check boundary condition
>>>>> +		 * PC = END - 8, EOC is executed
>>>>> +		 * PC = END, all CMDs are executed
>>>>> +		 */
>>>>> +		curr_pa = cmdq_thread_readl(thread, CMDQ_THR_CURR_ADDR);
>>>>> +		end_pa = cmdq_thread_readl(thread, CMDQ_THR_END_ADDR);
>>>>> +		if (curr_pa == end_pa - 8 || curr_pa == end_pa) {
>>>>
>>>> 8 refers to CMDQ_INST_SIZE, right?
>>>
>>> Yes, I will use CMDQ_INST_SIZE.
>>>
>>>>> +			/* set to this task directly */
>>>>> +			cmdq_thread_writel(thread, task->pa_base,
>>>>> +					   CMDQ_THR_CURR_ADDR);
>>>>> +		} else {
>>>>> +			cmdq_task_insert_into_thread(task);
>>>>> +
>>>>> +			if (thread == &cmdq->thread[CMDQ_THR_DISP_MAIN_IDX] ||
>>>>> +			    thread == &cmdq->thread[CMDQ_THR_DISP_SUB_IDX])
>>>>> +				cmdq_task_remove_wfe(task);
>>>>
>>>> We could do this check using the task->engine_flag, I suppose that's
>>>> easier to undestand then.
>>>
>>> Will use task->engine_flag.
>>>
>>>>> +
>>>>> +			smp_mb(); /* modify jump before enable thread */
>>>>> +		}
>>>>> +
>>>>> +		cmdq_thread_writel(thread, task->pa_base + task->command_size,
>>>>> +				   CMDQ_THR_END_ADDR);
>>>>> +		cmdq_thread_resume(thread);
>>>>> +	}
>>>>> +	list_move_tail(&task->list_entry, &thread->task_busy_list);
>>>>> +	spin_unlock_irqrestore(&cmdq->exec_lock, flags);
>>>>> +}
>>>>> +
>>>>> +static void cmdq_handle_error_done(struct cmdq *cmdq,
>>>>> +				   struct cmdq_thread *thread, u32 irq_flag)
>>>>> +{
>>>>> +	struct cmdq_task *task, *tmp, *curr_task = NULL;
>>>>> +	u32 curr_pa;
>>>>> +	struct cmdq_cb_data cmdq_cb_data;
>>>>> +	bool err;
>>>>> +
>>>>> +	if (irq_flag & CMDQ_THR_IRQ_ERROR)
>>>>> +		err = true;
>>>>> +	else if (irq_flag & CMDQ_THR_IRQ_DONE)
>>>>> +		err = false;
>>>>> +	else
>>>>> +		return;
>>>>> +
>>>>> +	curr_pa = cmdq_thread_readl(thread, CMDQ_THR_CURR_ADDR);
>>>>> +
>>>>> +	list_for_each_entry_safe(task, tmp, &thread->task_busy_list,
>>>>> +				 list_entry) {
>>>>> +		if (curr_pa >= task->pa_base &&
>>>>> +		    curr_pa < (task->pa_base + task->command_size))
>>>>
>>>> What are you checking here? It seems as if you make some implcit
>>>> assumptions about pa_base and the order of execution of commands in the
>>>> thread. Is it save to do so? Does dma_alloc_coherent give any guarantees
>>>> about dma_handle?
>>>
>>> 1. Check what is the current running task in this GCE thread.
>>> 2. Yes.
>>> 3. Yes, CMDQ doesn't use iommu, so physical address is continuous.
>>>
>>
>> Yes, physical addresses might be continous, but AFAIK there is no
>> guarantee that the dma_handle address is steadily growing, when calling
>> dma_alloc_coherent. And if I understand the code correctly, you use this
>> assumption to decide if the task picked from task_busy_list is currently
>> executing. So I think this mecanism is not working.
>
> I don't use dma_handle address, and just use physical addresses.
>  From CPU's point of view, tasks are linked by the busy list.
>  From GCE's point of view, tasks are linked by the JUMP command.
>
>> In which cases does the HW thread raise an interrupt.
>> In case of error. When does CMDQ_THR_IRQ_DONE get raised?
>
> GCE will raise interrupt if any task is done or error.
> However, GCE is fast, so CPU may get multiple done tasks
> when it is running ISR.
>
> In case of error, that GCE thread will pause and raise interrupt.
> So, CPU may get multiple done tasks and one error task.
>

I think we should reimplement the ISR mechanism. Can't we just read 
CURR_IRQ_STATUS and THR_IRQ_STATUS in the handler and leave 
cmdq_handle_error_done to the thread_fn? You will need to pass 
information from the handler to thread_fn, but that shouldn't be an 
issue. AFAIK interrupts are disabled in the handler, so we should stay 
there as short as possible. Traversing task_busy_list is expensive, so 
we need to do it in a thread context.

I keep thinking about how to get rid of the two data structures, 
task_busy_list and the task_release_wq. We need the latter for the only 
sake of getting a timeout.

Did you have a look on how the mailbox framework handles this?
By the way, what is the reason to not implement the whole driver as a 
mailbox controller? For me, this driver looks like a good fit.

>>>>> +			curr_task = task;
>>>>> +		if (task->cb.cb) {
>>>>> +			cmdq_cb_data.err = curr_task ? err : false;
>>>>> +			cmdq_cb_data.data = task->cb.data;
>>>>> +			task->cb.cb(cmdq_cb_data);
>>>>> +		}
>>>>> +		task->task_state = (curr_task && err) ? TASK_STATE_ERROR :
>>>>> +				TASK_STATE_DONE;
>>>>> +		list_del(&task->list_entry);
>>>>> +		if (curr_task)
>>>>> +			break;
>>>>> +	}
>>>>> +
>>>>> +	wake_up(&thread->wait_task_done);
>>>>> +}
>>>>> +
>>>>> +static void cmdq_thread_irq_handler(struct cmdq *cmdq, int tid)
>>>>> +{
>>>>> +	struct cmdq_thread *thread = &cmdq->thread[tid];
>>>>> +	unsigned long flags = 0L;
>>>>> +	u32 irq_flag;
>>>>> +
>>>>> +	spin_lock_irqsave(&cmdq->exec_lock, flags);
>>>>> +
>>>>> +	irq_flag = cmdq_thread_readl(thread, CMDQ_THR_IRQ_STATUS);
>>>>> +	cmdq_thread_writel(thread, ~irq_flag, CMDQ_THR_IRQ_STATUS);
>>>>> +
>>>>> +	/*
>>>>> +	 * Another CPU core could run "release task" right before we acquire
>>>>> +	 * the spin lock, and thus reset / disable this GCE thread, so we
>>>>> +	 * need to check the enable bit of this GCE thread.
>>>>> +	 */
>>>>> +	if (!(cmdq_thread_readl(thread, CMDQ_THR_ENABLE_TASK) &
>>>>> +	      CMDQ_THR_ENABLED))
>>>>> +		irq_flag = 0;
>>>>
>>>> cmdq_handle_error_done just retuns in this case. Programming this way
>>>> just makes things confusing. What about:
>>>>
>>>> if (cmdq_thread_readl(thread, CMDQ_THR_ENABLE_TASK) &
>>>> 	      CMDQ_THR_ENABLED)
>>>> 	cmdq_handle_error_done(cmdq, thread, irq_flag);
>>>> else
>>>> 		irq_flag = 0;
>>>>
>>>> spin_unlock_irqrestore(&cmdq->exec_lock, flags);
>>>
>>> We still need to clear irq_flag if GCE thread is disabled.
>>> So, I think we can just return here.
>>>
>>> 	if (!(cmdq_thread_readl(thread, CMDQ_THR_ENABLE_TASK) &
>>> 	      CMDQ_THR_ENABLED))
>>> 		return;
>>>
>>> What do you think?
>>>
>>
>> No, you can't just return, you need to unlock the spinlock.
>> Anyway I would prefer it the other way round, as I put it in my last
>> mail. Just delete the else branch, we don't need to set irq_flag to zero.
>
> Sorry for my previous wrong reply since I merge your comment
> and CK's comment.
> http://lists.infradead.org/pipermail/linux-mediatek/2016-May/005547.html
> So, I will put this if condition into cmdq_task_handle_error_result()
> and then just return it if GCE thread is disabled.
>

You mean in cmdq_task_handle_done
We should rename this functions to not create confusion.

Regards,
Matthias

>>>>> +
>>>>> +	cmdq_handle_error_done(cmdq, thread, irq_flag);
>>>>> +	spin_unlock_irqrestore(&cmdq->exec_lock, flags);
>>>>> +}
>>>>> +
>>>>> +static irqreturn_t cmdq_irq_handler(int irq, void *dev)
>>>>> +{
>>>>> +	struct cmdq *cmdq = dev;
>>>>> +	u32 irq_status;
>>>>> +	int i;
>>>>> +
>>>>> +	irq_status = readl(cmdq->base + CMDQ_CURR_IRQ_STATUS);
>>>>> +	irq_status &= CMDQ_IRQ_MASK;
>>>>> +	irq_status ^= CMDQ_IRQ_MASK;
>>>>
>>>> irq_status can be much bigger then 3, which is the number of threads in
>>>> the system (CMDQ_THR_MAX_COUNT). So why we use this mask here isn't
>>>> clear to me.
>>>
>>> Our GCE hardware has 16 threads, but we only use 3 threads currently.
>>>
>>
>> Ok, but please use bitops here.
>
> Will use bitops.
>
>>>>> +
>>>>> +	if (!irq_status)
>>>>> +		return IRQ_NONE;
>>>>> +
>>>>> +	while (irq_status) {
>>>>> +		i = ffs(irq_status) - 1;
>>>>> +		irq_status &= ~BIT(i);
>>>>> +		cmdq_thread_irq_handler(cmdq, i);
>>>>> +	}
>>>>
>>>> Can you explain how the irq status register looks like, that would it
>>>> make much easier to understand what happens here.
>>>
>>> Bit 0 ~ 15 of irq status register represents GCE thread 0 ~ 15
>>> interrupt. 0 means asserting interrupt; 1 means no interrupt.
>>>
>>
>> Thanks, that helped. :)
>>
>>>>> +
>>>>> +	return IRQ_HANDLED;	
>>>>> +}
>>>>> +
>>>>> +static int cmdq_task_handle_error_result(struct cmdq_task *task)
>>>>
>>>> We never check the return values, why do we have them?
>>>
>>> Will drop return value.
>>>
>>>>> +{
>>>>> +	struct cmdq *cmdq = task->cmdq;
>>>>> +	struct device *dev = cmdq->dev;
>>>>> +	struct cmdq_thread *thread = task->thread;
>>>>> +	struct cmdq_task *next_task, *prev_task;
>>>>> +	u32 irq_flag;
>>>>> +
>>>>> +	/* suspend GCE thread to ensure consistency */
>>>>> +	WARN_ON(cmdq_thread_suspend(cmdq, thread) < 0);
>>>>> +
>>>>> +	/* ISR has handled this error task */
>>>>> +	if (task->task_state == TASK_STATE_ERROR) {
>>>>> +		next_task = list_first_entry_or_null(&thread->task_busy_list,
>>>>> +				struct cmdq_task, list_entry);
>>>>> +		if (next_task) /* move to next task */
>>>>> +			cmdq_thread_writel(thread, next_task->pa_base,
>>>>> +					   CMDQ_THR_CURR_ADDR);
>>>>
>>>> We have to do this, as we suppose that the thread did not reach the jump
>>>> instruction we put into it's command queue, right?
>>>
>>> Yes.
>>>
>>
>> So this should then go into it's own function. In wait_release_work,
>> something like this:
>>
>> if(task->task_state == TASK_STATE_ERROR)
>>        cmdq_task_handle_error(task)
>
> OK.
> I will write new function cmdq_task_handle_error() to handle error case.
>
>>>>> +		cmdq_thread_resume(thread);
>>>>> +		return -ECANCELED;
>>>>> +	}
>>>>> +
>>>>
>>>> if task_state != ERROR and != DONE. This means that the timeout of
>>>> task_release_wq has timed out, right?
>>>
>>> Yes.
>>>
>>>>> +	/*
>>>>> +	 * Save next_task and prev_task in advance
>>>>> +	 * since cmdq_handle_error_done will remove list_entry.
>>>>> +	 */
>>>>> +	next_task = prev_task = NULL;
>>>>> +	if (task->list_entry.next != &thread->task_busy_list)
>>>>> +		next_task = list_next_entry(task, list_entry);
>>>>> +	if (task->list_entry.prev != &thread->task_busy_list)
>>>>> +		prev_task = list_prev_entry(task, list_entry);
>>>>> +
>>>>> +	/*
>>>>> +	 * Although IRQ is disabled, GCE continues to execute.
>>>>> +	 * It may have pending IRQ before GCE thread is suspended,
>>>>> +	 * so check this condition again.
>>>>> +	 */
>>>>
>>>> The first thing we did in this function was suspending the thread. Why
>>>> do we need this then?
>>>
>>> Because timeout is CPU timeout not GCE timeout, GCE could just finish
>>> this task before the GCE thread is suspended.
>>>
>>
>> What are the reasons for a timeout? An error has happend, or the task is
>> still executing.
>
>  From GCE's point of view, this task is still executing.
> But, it could be an error of client.
> For example, task may never get event if display turn off hardware
> before waiting for task to finish its work.
>
>>>> To be honest this whole functions looks really like a design error. We
>>>> have to sperate the states much clearer so that it is possible to
>>>> understand what is happening in the GCE. Isn't it for example posible to
>>>> have worker queues for timed out tasks and tasks with an error? I'm not
>>>> sure how to do this, actually I'm not sure if I really understood how
>>>> this is supposed to work.
>>>
>>> GCE doesn't have timeout. The timeout is decided and controlled by CPU,
>>> so we check timeout in release work.
>>> For error and done, they are easy to check by register, and we have
>>> already created release work for timeout. So, I don't think we need to
>>> create work queue for each case.
>>>
>>> What do you think?
>>>
>>
>> I think, if we find in here, that the irq_flag is set, then the the
>> interrupt handler was triggered and is spinning the spinlock. If this is
>> not the case, we have a timeout and we handle this.
>
> I will write another function to handle error, and handle timeout here.
>
>>>> How much do we win, when we patch the thread command queue for every
>>>> task we add, instead of just taking one task after another from the
>>>> task_busy_list?
>>>
>>> GCE is used to help read/write registers with critical time limitation.
>>> Sometimes, client may ask to process multiple tasks in a short period
>>> of time, e.g. display flush multiple tasks for next vblank. So, CMDQ
>>> shouldn't limit to process one task after another from the
>>> task_busy_list. Currently, when interrupt or timeout, we will check
>>> how many tasks are done, and which one is error or timeout.
>>>
>>
>> So I suppose the device driver who use this are interested in throughput
>> and not in latency. The callback of every
>>
>>>>> +	irq_flag = cmdq_thread_readl(thread, CMDQ_THR_IRQ_STATUS);
>>>>> +	cmdq_handle_error_done(cmdq, thread, irq_flag);
>>>>> +	cmdq_thread_writel(thread, ~irq_flag, CMDQ_THR_IRQ_STATUS);
>>>>> +
>>>>> +	if (task->task_state == TASK_STATE_DONE) {
>>>>> +		cmdq_thread_resume(thread);
>>>>> +		return 0;
>>>>> +	}
>>>>> +
>>>>> +	if (task->task_state == TASK_STATE_ERROR) {
>>>>> +		dev_err(dev, "task 0x%p error\n", task);
>>>>> +		if (next_task) /* move to next task */
>>>>> +			cmdq_thread_writel(thread, next_task->pa_base,
>>>>> +					   CMDQ_THR_CURR_ADDR);
>>>>> +		cmdq_thread_resume(thread);
>>>>> +		return -ECANCELED;
>>>>> +	}
>>>>> +
>>>>> +	/* Task is running, so we force to remove it. */
>>>>> +	dev_err(dev, "task 0x%p timeout or killed\n", task);
>>>>> +	task->task_state = TASK_STATE_ERROR;
>>>>> +
>>>>> +	if (prev_task) {
>>>>> +		u64 *prev_va = prev_task->va_base;
>>>>> +		u64 *curr_va = task->va_base;
>>>>> +
>>>>> +		/* copy JUMP instruction */
>>>>> +		prev_va[prev_task->num_cmd - 1] = curr_va[task->num_cmd - 1];
>>>>> +
>>>>> +		cmdq_thread_invalidate_fetched_data(thread);
>>>>> +	} else if (next_task) { /* move to next task */
>>>>> +		cmdq_thread_writel(thread, next_task->pa_base,
>>>>> +				   CMDQ_THR_CURR_ADDR);
>>>>> +	}
>>>>> +
>>>>> +	list_del(&task->list_entry);
>>>>> +	cmdq_thread_resume(thread);
>>>>> +
>>>>> +	/* call cb here to prevent lock */
>>>>> +	if (task->cb.cb) {
>>>>> +		struct cmdq_cb_data cmdq_cb_data;
>>>>> +
>>>>> +		cmdq_cb_data.err = true;
>>>>> +		cmdq_cb_data.data = task->cb.data;
>>>>> +		task->cb.cb(cmdq_cb_data);
>>>>> +	}
>>>>> +
>>>>> +	return -ECANCELED;
>>>>> +}
>>>>> +
>>>>> +static void cmdq_task_wait_release_work(struct work_struct *work_item)
>>>>> +{
>>>>> +	struct cmdq_task *task = container_of(work_item, struct cmdq_task,
>>>>> +					      release_work);
>>>>> +	struct cmdq *cmdq = task->cmdq;
>>>>> +	struct cmdq_thread *thread = task->thread;
>>>>> +	unsigned long flags;
>>>>> +
>>>>> +	wait_event_timeout(thread->wait_task_done,
>>>>> +			   task->task_state != TASK_STATE_BUSY,
>>>>> +			   msecs_to_jiffies(CMDQ_TIMEOUT_MS));
>>>>> +
>>>>> +	spin_lock_irqsave(&cmdq->exec_lock, flags);
>>>>> +	if (task->task_state != TASK_STATE_DONE)
>>>>> +		cmdq_task_handle_error_result(task);
>>>>> +	if (list_empty(&thread->task_busy_list))
>>>>> +		cmdq_thread_disable(cmdq, thread);
>>>>> +	spin_unlock_irqrestore(&cmdq->exec_lock, flags);
>>>>> +
>>>>> +	/* release regardless of success or not */
>>>>> +	clk_disable_unprepare(cmdq->clock);
>>>>> +	cmdq_task_release(task);
>>>>> +}
>>>>> +
>>>>> +static void cmdq_task_wait_release_schedule(struct cmdq_task *task)
>>>>> +{
>>>>> +	struct cmdq *cmdq = task->cmdq;
>>>>> +
>>>>> +	INIT_WORK(&task->release_work, cmdq_task_wait_release_work);
>>>>> +	queue_work(cmdq->task_release_wq, &task->release_work);
>>>>> +}
>>>>> +
>>>>> +static int cmdq_rec_realloc_cmd_buffer(struct cmdq_rec *rec, size_t size)
>>>>> +{
>>>>> +	void *new_buf;
>>>>> +
>>>>> +	new_buf = krealloc(rec->buf, size, GFP_KERNEL | __GFP_ZERO);
>>>>> +	if (!new_buf)
>>>>> +		return -ENOMEM;
>>>>> +	rec->buf = new_buf;
>>>>> +	rec->buf_size = size;
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +struct cmdq_base *cmdq_register_device(struct device *dev)
>>>>> +{
>>>>> +	struct cmdq_base *cmdq_base;
>>>>> +	struct resource res;
>>>>> +	int subsys;
>>>>> +	u32 base;
>>>>> +
>>>>> +	if (of_address_to_resource(dev->of_node, 0, &res))
>>>>> +		return NULL;
>>>>> +	base = (u32)res.start;
>>>>> +
>>>>> +	subsys = cmdq_subsys_base_to_id(base >> 16);
>>>>> +	if (subsys < 0)
>>>>> +		return NULL;
>>>>> +
>>>>> +	cmdq_base = devm_kmalloc(dev, sizeof(*cmdq_base), GFP_KERNEL);
>>>>> +	if (!cmdq_base)
>>>>> +		return NULL;
>>>>> +	cmdq_base->subsys = subsys;
>>>>> +	cmdq_base->base = base;
>>>>> +
>>>>> +	return cmdq_base;
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_register_device);
>>>>> +
>>>>> +int cmdq_rec_create(struct device *dev, u64 engine_flag,
>>>>> +		    struct cmdq_rec **rec_ptr)
>>>>> +{
>>>>> +	struct cmdq_rec *rec;
>>>>> +	int err;
>>>>> +
>>>>> +	rec = kzalloc(sizeof(*rec), GFP_KERNEL);
>>>>> +	if (!rec)
>>>>> +		return -ENOMEM;
>>>>> +	rec->cmdq = dev_get_drvdata(dev);
>>>>> +	rec->engine_flag = engine_flag;
>>>>> +	err = cmdq_rec_realloc_cmd_buffer(rec, CMDQ_INITIAL_CMD_BLOCK_SIZE);
>>>>
>>>> Just pass PAGE_SIZE here, no need for CMDQ_INITIAL_CMD_BLOCK_SIZE.
>>>
>>> Will do.
>>>
>>>>> +	if (err < 0) {
>>>>> +		kfree(rec);
>>>>> +		return err;
>>>>> +	}
>>>>> +	*rec_ptr = rec;
>>>>> +	return 0;
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_create);
>>>>> +
>>>>> +static int cmdq_rec_append_command(struct cmdq_rec *rec, enum cmdq_code code,
>>>>> +				   u32 arg_a, u32 arg_b)
>>>>> +{
>>>>> +	u64 *cmd_ptr;
>>>>> +	int err;
>>>>> +
>>>>> +	if (WARN_ON(rec->finalized))
>>>>> +		return -EBUSY;
>>>>> +	if (code < CMDQ_CODE_MOVE || code > CMDQ_CODE_EOC)
>>>>> +		return -EINVAL;
>>>>
>>>> cmdq_rec_append_command is just called from inside this driver and code
>>>> is a enum. We can expect it to be correct, no need for this check.
>>>
>>> Will drop this check.
>>>
>>>>> +	if (unlikely(rec->command_size + CMDQ_INST_SIZE > rec->buf_size)) {
>>>>
>>>> command_size is the offset into the buffer to which a new command is
>>>> written, so this name is highly confusing. I wonder if this would be
>>>> easier to understand if we redefine command_size to something like the
>>>> number of commands and divide/multiply CMDQ_INST_SIZE where this is needed.
>>>
>>> I can rename command_size to cmd_buf_size and calculate num_cmd by
>>> dividing CMDQ_INST_SIZE.
>>> What do you think?
>>>
>>>>> +		err = cmdq_rec_realloc_cmd_buffer(rec, rec->buf_size * 2);
>>>>> +		if (err < 0)
>>>>> +			return err;
>>>>> +	}
>>>>> +	cmd_ptr = rec->buf + rec->command_size;
>>>>> +	(*cmd_ptr) = (u64)((code << CMDQ_OP_CODE_SHIFT) | arg_a) << 32 | arg_b;
>>>>> +	rec->command_size += CMDQ_INST_SIZE;
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +int cmdq_rec_write(struct cmdq_rec *rec, u32 value, struct cmdq_base *base,
>>>>> +		   u32 offset)
>>>>> +{
>>>>> +	u32 arg_a = ((base->base + offset) & CMDQ_ARG_A_WRITE_MASK) |
>>>>> +		    ((base->subsys & CMDQ_SUBSYS_MASK) << CMDQ_SUBSYS_SHIFT);
>>>>
>>>> base->subsys is the id from gce_sybsys, so we can expect it to be
>>>> correct, no need to mask with CMDQ_SUBSYS_MASK.
>>>
>>> Will drop it.
>>>
>>>>> +	return cmdq_rec_append_command(rec, CMDQ_CODE_WRITE, arg_a, value);
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_write);
>>>>> +
>>>>> +int cmdq_rec_write_mask(struct cmdq_rec *rec, u32 value,
>>>>> +			struct cmdq_base *base, u32 offset, u32 mask)
>>>>> +{
>>>>> +	u32 offset_mask = offset;
>>>>> +	int err;
>>>>> +
>>>>> +	if (mask != 0xffffffff) {
>>>>> +		err = cmdq_rec_append_command(rec, CMDQ_CODE_MOVE, 0, ~mask);
>>>>> +		if (err < 0)
>>>>> +			return err;
>>>>> +		offset_mask |= CMDQ_WRITE_ENABLE_MASK;
>>>>> +	}
>>>>> +	return cmdq_rec_write(rec, value, base, offset_mask);
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_write_mask);
>>>>> +
>>>>> +int cmdq_rec_wfe(struct cmdq_rec *rec, enum cmdq_event event)
>>>>> +{
>>>>> +	u32 arg_b;
>>>>> +
>>>>> +	if (event >= CMDQ_MAX_HW_EVENT_COUNT || event < 0)
>>>>> +		return -EINVAL;
>>>>> +
>>>>> +	/*
>>>>> +	 * bit 0-11: wait value
>>>>> +	 * bit 15: 1 - wait, 0 - no wait
>>>>> +	 * bit 16-27: update value
>>>>> +	 * bit 31: 1 - update, 0 - no update
>>>>> +	 */
>>>>
>>>> I don't understand this comments. What are they for?
>>>
>>> This is for WFE command. I will comment it.
>>>
>>>>> +	arg_b = CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | CMDQ_WFE_WAIT_VALUE;
>>>>> +	return cmdq_rec_append_command(rec, CMDQ_CODE_WFE, event, arg_b);
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_wfe);
>>>>> +
>>>>> +int cmdq_rec_clear_event(struct cmdq_rec *rec, enum cmdq_event event)
>>>>> +{
>>>>> +	if (event >= CMDQ_MAX_HW_EVENT_COUNT || event < 0)
>>>>> +		return -EINVAL;
>>>>> +
>>>>> +	return cmdq_rec_append_command(rec, CMDQ_CODE_WFE, event,
>>>>> +				       CMDQ_WFE_UPDATE);
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_clear_event);
>>>>> +
>>>>> +static int cmdq_rec_finalize(struct cmdq_rec *rec)
>>>>> +{
>>>>> +	int err;
>>>>> +
>>>>> +	if (rec->finalized)
>>>>> +		return 0;
>>>>> +
>>>>> +	/* insert EOC and generate IRQ for each command iteration */
>>>>> +	err = cmdq_rec_append_command(rec, CMDQ_CODE_EOC, 0, CMDQ_EOC_IRQ_EN);
>>>>> +	if (err < 0)
>>>>> +		return err;
>>>>> +
>>>>> +	/* JUMP to end */
>>>>> +	err = cmdq_rec_append_command(rec, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
>>>>> +	if (err < 0)
>>>>> +		return err;
>>>>> +
>>>>
>>>> Does this need to be atomic?
>>>> What happens if after CODE_EOC and before CODE_JUMP some
>>>> write/read/event gets added?
>>>> What happens if more commands get added to the queue after CODE_JUMP,
>>>> but before finalized is set to true. Why don't you use atomic functions
>>>> to access finalized?
>>>
>>> Since cmdq_rec doesn't guarantee thread safe, mutex is needed when
>>> client uses cmdq_rec.
>>>
>>
>> Well I think that rec->finalized tries to implement this, but might
>> fail, if two kernel threads work on the same cmdq_rec.
>>
>>>>> +	rec->finalized = true;
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +int cmdq_rec_flush_async(struct cmdq_rec *rec, cmdq_async_flush_cb cb,
>>>>> +			 void *data)
>>>>> +{
>>>>> +	struct cmdq *cmdq = rec->cmdq;
>>>>> +	struct cmdq_task *task;
>>>>> +	struct cmdq_task_cb task_cb;
>>>>> +	struct cmdq_thread *thread;
>>>>> +	int err;
>>>>> +
>>>>> +	mutex_lock(&cmdq->task_mutex);
>>>>> +	if (cmdq->suspended) {
>>>>> +		dev_err(cmdq->dev, "%s is called after suspended\n", __func__);
>>>>> +		mutex_unlock(&cmdq->task_mutex);
>>>>> +		return -EPERM;
>>>>> +	}
>>>>> +
>>>>> +	err = cmdq_rec_finalize(rec);
>>>>> +	if (err < 0) {
>>>>> +		mutex_unlock(&cmdq->task_mutex);
>>>>> +		return err;
>>>>> +	}
>>>>> +
>>>>> +	task_cb.cb = cb;
>>>>> +	task_cb.data = data;
>>>>> +	task = cmdq_task_acquire(rec, task_cb);
>>>>> +	if (!task) {
>>>>> +		mutex_unlock(&cmdq->task_mutex);
>>>>> +		return -EFAULT;
>>>>> +	}
>>>>> +
>>>>> +	thread = &cmdq->thread[cmdq_eng_get_thread(task->engine_flag)];
>>>>> +	cmdq_task_exec(task, thread);
>>>>> +	cmdq_task_wait_release_schedule(task);
>>>>> +	mutex_unlock(&cmdq->task_mutex);
>>>>> +	return 0;
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_flush_async);
>>>>> +
>>>>> +struct cmdq_flush_completion {
>>>>> +	struct completion cmplt;
>>>>> +	bool err;
>>>>> +};
>>>>> +
>>>>> +static int cmdq_rec_flush_cb(struct cmdq_cb_data data)
>>>>> +{
>>>>> +	struct cmdq_flush_completion *cmplt = data.data;
>>>>> +
>>>>> +	cmplt->err = data.err;
>>>>> +	complete(&cmplt->cmplt);
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +int cmdq_rec_flush(struct cmdq_rec *rec)
>>>>> +{
>>>>> +	struct cmdq_flush_completion cmplt;
>>>>> +	int err;
>>>>> +
>>>>> +	init_completion(&cmplt.cmplt);
>>>>> +	err = cmdq_rec_flush_async(rec, cmdq_rec_flush_cb, &cmplt);
>>>>> +	if (err < 0)
>>>>> +		return err;
>>>>> +	wait_for_completion(&cmplt.cmplt);
>>>>> +	return cmplt.err ? -EFAULT : 0;
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_flush);
>>>>> +
>>>>> +void cmdq_rec_destroy(struct cmdq_rec *rec)
>>>>> +{
>>>>> +	kfree(rec->buf);
>>>>> +	kfree(rec);
>>>>> +}
>>>>> +EXPORT_SYMBOL(cmdq_rec_destroy);
>>>>> +
>>>>> +static bool cmdq_task_is_empty(struct cmdq *cmdq)
>>>>> +{
>>>>> +	struct cmdq_thread *thread;
>>>>> +	int i;
>>>>> +
>>>>> +	for (i = 0; i < ARRAY_SIZE(cmdq->thread); i++) {
>>>>> +		thread = &cmdq->thread[i];
>>>>> +		if (!list_empty(&thread->task_busy_list))
>>>>> +			return false;
>>>>> +	}
>>>>> +	return true;
>>>>> +}
>>>>> +
>>>>> +static int cmdq_suspend(struct device *dev)
>>>>> +{
>>>>> +	struct cmdq *cmdq = dev_get_drvdata(dev);
>>>>> +	u32 exec_threads;
>>>>> +
>>>>> +	mutex_lock(&cmdq->task_mutex);
>>>>> +	cmdq->suspended = true;
>>>>> +	mutex_unlock(&cmdq->task_mutex);
>>>>> +
>>>>> +	exec_threads = readl(cmdq->base + CMDQ_CURR_LOADED_THR);
>>>>> +	if ((exec_threads & CMDQ_THR_EXECUTING) && !cmdq_task_is_empty(cmdq)) {
>>>>> +		dev_err(dev, "wait active tasks timeout.\n");
>>>>> +		flush_workqueue(cmdq->task_release_wq);
>>>>> +	}
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int cmdq_resume(struct device *dev)
>>>>> +{
>>>>> +	struct cmdq *cmdq = dev_get_drvdata(dev);
>>>>> +
>>>>> +	cmdq->suspended = false;
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int cmdq_remove(struct platform_device *pdev)
>>>>> +{
>>>>> +	struct cmdq *cmdq = platform_get_drvdata(pdev);
>>>>> +
>>>>> +	destroy_workqueue(cmdq->task_release_wq);
>>>>> +	cmdq->task_release_wq = NULL;
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int cmdq_probe(struct platform_device *pdev)
>>>>> +{
>>>>> +	struct device *dev = &pdev->dev;
>>>>> +	struct device_node *node = dev->of_node;
>>>>> +	struct resource *res;
>>>>> +	struct cmdq *cmdq;
>>>>> +	int err, i;
>>>>> +
>>>>> +	cmdq = devm_kzalloc(dev, sizeof(*cmdq), GFP_KERNEL);
>>>>> +	if (!cmdq)
>>>>> +		return -ENOMEM;
>>>>> +	cmdq->dev = dev;
>>>>> +
>>>>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>>> +	cmdq->base = devm_ioremap_resource(dev, res);
>>>>> +	if (IS_ERR(cmdq->base)) {
>>>>> +		dev_err(dev, "failed to ioremap gce\n");
>>>>> +		return PTR_ERR(cmdq->base);
>>>>> +	}
>>>>> +
>>>>> +	cmdq->irq = irq_of_parse_and_map(node, 0);
>>>>> +	if (!cmdq->irq) {
>>>>> +		dev_err(dev, "failed to get irq\n");
>>>>> +		return -EINVAL;
>>>>> +	}
>>>>> +
>>>>> +	dev_dbg(dev, "cmdq device: addr:0x%p, va:0x%p, irq:%d\n",
>>>>> +		dev, cmdq->base, cmdq->irq);
>>>>> +
>>>>> +	mutex_init(&cmdq->task_mutex);
>>>>> +	spin_lock_init(&cmdq->exec_lock);
>>>>> +	cmdq->task_release_wq = alloc_ordered_workqueue(
>>>>> +			"%s", WQ_MEM_RECLAIM | WQ_HIGHPRI,
>>>>> +			"cmdq_task_wait_release");
>>>>> +
>>>>> +	for (i = 0; i < ARRAY_SIZE(cmdq->thread); i++) {
>>>>> +		cmdq->thread[i].base = cmdq->base + CMDQ_THR_BASE +
>>>>> +				CMDQ_THR_SHIFT * i;
>>>>> +		init_waitqueue_head(&cmdq->thread[i].wait_task_done);
>>>>> +		INIT_LIST_HEAD(&cmdq->thread[i].task_busy_list);
>>>>> +	}
>>>>> +
>>>>> +	platform_set_drvdata(pdev, cmdq);
>>>>> +
>>>>> +	err = devm_request_irq(dev, cmdq->irq, cmdq_irq_handler, IRQF_SHARED,
>>>>> +			       CMDQ_DRIVER_DEVICE_NAME, cmdq);
>>>>> +	if (err < 0) {
>>>>> +		dev_err(dev, "failed to register ISR (%d)\n", err);
>>>>> +		goto fail;
>>>>> +	}
>>>>> +
>>>>> +	cmdq->clock = devm_clk_get(dev, CMDQ_CLK_NAME);
>>>>> +	if (IS_ERR(cmdq->clock)) {
>>>>> +		dev_err(dev, "failed to get clk:%s\n", CMDQ_CLK_NAME);
>>>>> +		err = PTR_ERR(cmdq->clock);
>>>>> +		goto fail;
>>>>> +	}
>>>>> +	return 0;
>>>>> +
>>>>> +fail:
>>>>> +	cmdq_remove(pdev);
>>>>> +	return err;
>>>>> +}
>>>>> +
>>>>> +static const struct dev_pm_ops cmdq_pm_ops = {
>>>>> +	.suspend = cmdq_suspend,
>>>>> +	.resume = cmdq_resume,
>>>>> +};
>>>>> +
>>>>> +static const struct of_device_id cmdq_of_ids[] = {
>>>>> +	{.compatible = "mediatek,mt8173-gce",},
>>>>> +	{}
>>>>> +};
>>>>> +
>>>>> +static struct platform_driver cmdq_drv = {
>>>>> +	.probe = cmdq_probe,
>>>>> +	.remove = cmdq_remove,
>>>>> +	.driver = {
>>>>> +		.name = CMDQ_DRIVER_DEVICE_NAME,
>>>>> +		.owner = THIS_MODULE,
>>>>> +		.pm = &cmdq_pm_ops,
>>>>> +		.of_match_table = cmdq_of_ids,
>>>>> +	}
>>>>> +};
>>>>> +
>>>>> +builtin_platform_driver(cmdq_drv);
>>>>> diff --git a/include/soc/mediatek/cmdq.h b/include/soc/mediatek/cmdq.h
>>>>> new file mode 100644
>>>>> index 0000000..60eef3d
>>>>> --- /dev/null
>>>>> +++ b/include/soc/mediatek/cmdq.h
>>>>> @@ -0,0 +1,197 @@
>>>>> +/*
>>>>> + * Copyright (c) 2015 MediaTek Inc.
>>>>> + *
>>>>> + * This program is free software; you can redistribute it and/or modify
>>>>> + * it under the terms of the GNU General Public License version 2 as
>>>>> + * published by the Free Software Foundation.
>>>>> + *
>>>>> + * This program is distributed in the hope that it will be useful,
>>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>>>> + * GNU General Public License for more details.
>>>>> + */
>>>>> +
>>>>> +#ifndef __MTK_CMDQ_H__
>>>>> +#define __MTK_CMDQ_H__
>>>>> +
>>>>> +#include <linux/platform_device.h>
>>>>> +#include <linux/types.h>
>>>>> +
>>>>> +enum cmdq_eng {
>>>>> +	CMDQ_ENG_DISP_AAL,
>>>>> +	CMDQ_ENG_DISP_COLOR0,
>>>>> +	CMDQ_ENG_DISP_COLOR1,
>>>>> +	CMDQ_ENG_DISP_DPI0,
>>>>> +	CMDQ_ENG_DISP_DSI0,
>>>>> +	CMDQ_ENG_DISP_DSI1,
>>>>> +	CMDQ_ENG_DISP_GAMMA,
>>>>> +	CMDQ_ENG_DISP_OD,
>>>>> +	CMDQ_ENG_DISP_OVL0,
>>>>> +	CMDQ_ENG_DISP_OVL1,
>>>>> +	CMDQ_ENG_DISP_PWM0,
>>>>> +	CMDQ_ENG_DISP_PWM1,
>>>>> +	CMDQ_ENG_DISP_RDMA0,
>>>>> +	CMDQ_ENG_DISP_RDMA1,
>>>>> +	CMDQ_ENG_DISP_RDMA2,
>>>>> +	CMDQ_ENG_DISP_UFOE,
>>>>> +	CMDQ_ENG_DISP_WDMA0,
>>>>> +	CMDQ_ENG_DISP_WDMA1,
>>>>> +	CMDQ_ENG_MAX,
>>>>> +};
>>>>> +
>>>>> +/* events for CMDQ and display */
>>>>> +enum cmdq_event {
>>>>> +	/* Display start of frame(SOF) events */
>>>>> +	CMDQ_EVENT_DISP_OVL0_SOF = 11,
>>>>> +	CMDQ_EVENT_DISP_OVL1_SOF = 12,
>>>>> +	CMDQ_EVENT_DISP_RDMA0_SOF = 13,
>>>>> +	CMDQ_EVENT_DISP_RDMA1_SOF = 14,
>>>>> +	CMDQ_EVENT_DISP_RDMA2_SOF = 15,
>>>>> +	CMDQ_EVENT_DISP_WDMA0_SOF = 16,
>>>>> +	CMDQ_EVENT_DISP_WDMA1_SOF = 17,
>>>>> +	/* Display end of frame(EOF) events */
>>>>> +	CMDQ_EVENT_DISP_OVL0_EOF = 39,
>>>>> +	CMDQ_EVENT_DISP_OVL1_EOF = 40,
>>>>> +	CMDQ_EVENT_DISP_RDMA0_EOF = 41,
>>>>> +	CMDQ_EVENT_DISP_RDMA1_EOF = 42,
>>>>> +	CMDQ_EVENT_DISP_RDMA2_EOF = 43,
>>>>> +	CMDQ_EVENT_DISP_WDMA0_EOF = 44,
>>>>> +	CMDQ_EVENT_DISP_WDMA1_EOF = 45,
>>>>> +	/* Mutex end of frame(EOF) events */
>>>>> +	CMDQ_EVENT_MUTEX0_STREAM_EOF = 53,
>>>>> +	CMDQ_EVENT_MUTEX1_STREAM_EOF = 54,
>>>>> +	CMDQ_EVENT_MUTEX2_STREAM_EOF = 55,
>>>>> +	CMDQ_EVENT_MUTEX3_STREAM_EOF = 56,
>>>>> +	CMDQ_EVENT_MUTEX4_STREAM_EOF = 57,
>>>>> +	/* Display underrun events */
>>>>> +	CMDQ_EVENT_DISP_RDMA0_UNDERRUN = 63,
>>>>> +	CMDQ_EVENT_DISP_RDMA1_UNDERRUN = 64,
>>>>> +	CMDQ_EVENT_DISP_RDMA2_UNDERRUN = 65,
>>>>> +	/* Keep this at the end of HW events */
>>>>> +	CMDQ_MAX_HW_EVENT_COUNT = 260,
>>>>> +};
>>>>> +
>>>>> +struct cmdq_cb_data {
>>>>> +	bool	err;
>>>>> +	void	*data;
>>>>> +};
>>>>> +
>>>>> +typedef int (*cmdq_async_flush_cb)(struct cmdq_cb_data data);
>>>>> +
>>>>> +struct cmdq_task;
>>>>> +struct cmdq;
>>>>> +
>>>>> +struct cmdq_rec {
>>>>> +	struct cmdq		*cmdq;
>>>>> +	u64			engine_flag;
>>>>> +	size_t			command_size;
>>>>> +	void			*buf;
>>>>> +	size_t			buf_size;
>>>>> +	bool			finalized;
>>>>> +};
>>
>> Why do we need cmdq_rec at all? Can't we just use the cmdq_task for that
>> and this way make the driver less complex?
>
> There are two main reasons for cmdq_rec.
> 1. It is slow to access dma too frequently.
>     So, we append commands to cacheable memory, and then flush to dma.
> 2. cmdq_rec is not thread safe, but cmdq_task needs thread safe.
>     If we merge them, we need to take care of some synchronization
>     issues.
>
>>>>> +
>>>>> +struct cmdq_base {
>>>>> +	int	subsys;
>>>>> +	u32	base;
>>>>
>>>> subsys can always be calculated via cmdq_subsys_base_to_id(base >> 16)
>>>> so we can get rid of the struct, right?
>>>
>>> Current subsys method is based on previous comment from Daniel Kurtz.
>>> Please take a look of our previous discussion.
>>> http://lists.infradead.org/pipermail/linux-mediatek/2016-February/004483.html
>>> Thanks.
>>>
>>
>> I have to look deeper into this, but from what I read, the proposal from
>> Daniel [1] seems good to me.
>>
>> [1] https://patchwork.kernel.org/patch/8068311/
>
> The initial proposal has some problem, so please see the follow-up
> discussions. Thanks.
> http://lists.infradead.org/pipermail/linux-mediatek/2016-February/003972.html
> http://lists.infradead.org/pipermail/linux-mediatek/2016-February/004483.html
>
>
>>>>> +};
>>>>> +
>>>>> +/**
>>>>> + * cmdq_register_device() - register device which needs CMDQ
>>>>> + * @dev:		device
>>>>> + *
>>>>> + * Return: cmdq_base pointer or NULL for failed
>>>>> + */
>>>>> +struct cmdq_base *cmdq_register_device(struct device *dev);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_create() - create command queue record
>>>>> + * @dev:		device
>>>>> + * @engine_flag:	command queue engine flag
>>>>> + * @rec_ptr:		command queue record pointer to retrieve cmdq_rec
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + */
>>>>> +int cmdq_rec_create(struct device *dev, u64 engine_flag,
>>>>> +		    struct cmdq_rec **rec_ptr);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_write() - append write command to the command queue record
>>>>> + * @rec:	the command queue record
>>>>> + * @value:	the specified target register value
>>>>> + * @base:	the command queue base
>>>>> + * @offset:	register offset from module base
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + */
>>>>> +int cmdq_rec_write(struct cmdq_rec *rec, u32 value,
>>>>> +		   struct cmdq_base *base, u32 offset);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_write_mask() - append write command with mask to the command
>>>>> + *			   queue record
>>>>> + * @rec:	the command queue record
>>>>> + * @value:	the specified target register value
>>>>> + * @base:	the command queue base
>>>>> + * @offset:	register offset from module base
>>>>> + * @mask:	the specified target register mask
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + */
>>>>> +int cmdq_rec_write_mask(struct cmdq_rec *rec, u32 value,
>>>>> +			struct cmdq_base *base, u32 offset, u32 mask);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_wfe() - append wait for event command to the command queue reco	rd
>>>>
>>>> reco rd -> record
>>>
>>> Will fix it.
>>>
>>>> Regards,
>>>> Matthias
>>>>
>>>>> + * @rec:	the command queue record
>>>>> + * @event:	the desired event type to "wait and CLEAR"
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + */
>>>>> +int cmdq_rec_wfe(struct cmdq_rec *rec, enum cmdq_event event);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_clear_event() - append clear event command to the command queue
>>>>> + *			    record
>>>>> + * @rec:	the command queue record
>>>>> + * @event:	the desired event to be cleared
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + */
>>>>> +int cmdq_rec_clear_event(struct cmdq_rec *rec, enum cmdq_event event);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_flush() - trigger CMDQ to execute the recorded commands
>>>>> + * @rec:	the command queue record
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + *
>>>>> + * Trigger CMDQ to execute the recorded commands. Note that this is a
>>>>> + * synchronous flush function. When the function returned, the recorded
>>>>> + * commands have been done.
>>>>> + */
>>>>> +int cmdq_rec_flush(struct cmdq_rec *rec);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_flush_async() - trigger CMDQ to asynchronously execute the recorded
>>>>> + *			    commands and call back after ISR is finished
>>>>> + * @rec:	the command queue record
>>>>> + * @cb:		called in the end of CMDQ ISR
>>>>> + * @data:	this data will pass back to cb
>>>>> + *
>>>>> + * Return: 0 for success; else the error code is returned
>>>>> + *
>>>>> + * Trigger CMDQ to asynchronously execute the recorded commands and call back
>>>>> + * after ISR is finished. Note that this is an ASYNC function. When the function
>>>>> + * returned, it may or may not be finished. The ISR callback function is called
>>>>> + * in the end of ISR.
>>
>> "The callback is called from the ISR."
>>
>> Regards,
>> Matthias
>>
>>>>> + */
>>>>> +int cmdq_rec_flush_async(struct cmdq_rec *rec, cmdq_async_flush_cb cb,
>>>>> +			 void *data);
>>>>> +
>>>>> +/**
>>>>> + * cmdq_rec_destroy() - destroy command queue record
>>>>> + * @rec:	the command queue record
>>>>> + */
>>>>> +void cmdq_rec_destroy(struct cmdq_rec *rec);
>>>>> +
>>>>> +#endif	/* __MTK_CMDQ_H__ */
>>>>>
>>>
>>> Thanks,
>>> HS
>>>
>
> Thanks,
> HS
>